I've been asked to test a 3-D system that uses a single camera, single lens approach.

I will be shooting 48 fps @ 1080p for sync sound (to derive 24fps real time, using alternating frames for left eye and right eye). I realize there are temporal issues with this concept, but that's not germane to my question. I'm not sure what it is they're doing in post and am bound by an NDA at this point not to discuss anything about the system.

I'd like to use a 2/3-inch CAMCORDER (for a smaller footprint than the F-23 because there's a lot of water/ underwater work).

Possibly. Not my expertise. I assume you mean because it's not a multiple of 23.98...? Point now moot due to update.

Jacques Haitkin DP
San Francisco

Vince Hogan writes :

>> Would you have audio sync drift issues at 48 fps?

Jacques Haitkin wrote:

>> Possibly. Not my expertise. I assume you mean because it's not a multiple of 23.98...? Point now >>moot due to update.

Hi everyone,

The F23 / F35 / 9000 can shoot 48fps as Mitch pointed out. But that is an OFFSPEED framerate, so no sync sound at all.

I ran into that question when I prepped my last 3D project. There might be a DCI standard for screening 2x 48fps for 3D (48 fps per eye), but there is no camera around (at least not that I am aware of), that can record sync sound @ 48fps. I don't think there's a 48fps Audiodeck or a 48fps Timecode (I guess this could possibly be solved using 24PsF TC?) but 48 fps production
is not ready yet at all...

>> there is no camera around (at least not that I am aware of), that can record sync sound @ 48fps.

But I presume it would be speed-accurate enough to hold synch in a double-system setup? One might wonder what the application would be, but ride films would love to shoot and project at 60P or greater.

Tim Sassoon
SFD
Santa Monica, CA

Florian Rettich writes:

<< The F23 / F35 / 9000 can shoot 48fps as Mitch pointed out. But that is an OFFSPEED framerate, >>so no sync sound at all.

Whatever speed you're shooting at, you can do a high-quality *analog* real-time transfer from your original audio recording medium to whatever editing timebase you're using. A second of time is a second of time, regardless of your chosen framerate.

If you play back on the original recording unit your clock speed will be spot-on and there should be no speed drift over time. You won't have preserved any original timecode, but as long as you use head- or tail-slates (or even sync up by eye) you should come out smelling like a rose.

Details may vary with your equipment and your NLE, but that's the general idea.

Granted, the clocks in your camera and recorder may not be dead accurate, but these days the discrepancy should amount to less than a frame over a time span that will permit adding or subtracting a frame of audio seamlessly.

Dan "digital brain, analog soul" Drasin
Producer/DP
Marin County, CA

One hurdle with 48fps is there's not timecode format for it so you have to use 24fps with fake fields.